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T ALL WHOM IT MAY GONCERN:

v Be it known that I, EDWIN L. BRAbY, of New Orleans, .in the parish of Orleans, and State of Louisiana,

huye invented a new and useful Improvement in Boats for Dredging under Water; and I-do hereby declare that the following is a full, clear, and cxaot description of the same, reference being had to the annexed drawings, making part of this specication, in which- Figure 1 is avertical longitudinal section, and Figure 2 is a horizontal section. M

The same letters are employed for thc designation of the same parts in both figures.

' This excavator consists of a strong boat, propelled by one or two propellers placed'iu the stern of the boat. I prefer two propellers, as aiording greater powerv and rendering the -boatmore manageable in steering in Vcrooked channels. This propeller is drawn in the ordinary manner, by steam-engines of ordinary construction.

Near the bowof tho boat I place another steam-engine, driving what I call themud-fan,v which projects from and in front of the bow of the boat. This is formed by a 'set-of revolving blades, shown at A, turned like the propellers by a shaft passingvthrough a stuffing-box, D. The blades are shaped somewhat like those of ,erpropeller, but they are sharper on their points and less inclined on their faces. These blades should exten-d, say,

two feet below the bottom of the boat, and their object is, by their rapid revolution, to displace the sand and mud on the bottom, andstirring them up to mix them with'thewater so that they may be carried o by the currnt. The motion of the mud-fan tends to draw forward the boat, assisting thelpropellers. All the engines may be driven by one set of boilers, F, placed emidships. 1 i

In order that the mud-fan may be brought in contact with the bottom, I construct the boat with a series of watertight compartments, E, placed in thehow and stern, and on each side of the centre, amidships, .into

which the 'water may befpcrmitted to iiow through pipes so as to sink the vessel -to the required depth; the" compartments Vbeing so placed and proportioned that the vessel shall sink with an eve'n keel, by which the effective action of the fmud-fan," the-propellers, and steering-apparatus is preserved, the boat being manageable at any depth. A large pump, B, driven by the engine, is connected bypipcs with 'all the compartments, so that the water may be pumped out when necessary to raise the boat.

I am aware that boats have been constructed, with compartments -t'o be iilled with water, to sink the dredging-mechanism to the bottom, by loading the eud1of the boat in which su-ch mechanism is placed; but this construction issubject to the disadvantage of requiring more complicated maehineryfor dredging, in order 'that it may be accommodated to the inclination of the boat; und to the further disadvantage, that the boats thus.

inclined are comparatively unmanngeable.

What I claim Vas my invention, :vnd desire to secure by Letters Patent, is

1. A dredging-boat constructed with a series of water-tight compartments, so proportioned and arranged that, as they are iilled with water, thc boat shall preserve anmcven keel, and the dredging-mechanism bc brought into action without any adjusting-devices, substantially as set forth.

2.4 The eombinatien of the mud-fan A, attached-to a rigid shaft, and a boat containing a series of watertight compartments, E, so adjusted as to cause the boat to settle on an even' keel, as thc compartments are filled `with water, and a pump, B, for exhausting the water from all the compartments, substantially as set for-th.

EDWIN L. BRADY.

. Witnesses:

It. MASON, L. MURPHY. 

